Field of the Invention
The disclosure generally relates to an antenna structure, and more particularly, to a small-size antenna structure.
Description of the Related Art
With advancements in mobile communication technology, mobile devices such as portable computers, mobile phones, multimedia players, and other hybrid functional portable electronic devices have become more common. To satisfy user demand, mobile devices can usually perform wireless communication functions. Some devices cover a large wireless communication area; these include mobile phones using 2G, 3G, and LTE (Long Term Evolution) systems and using frequency bands of 700 MHz, 850 MHz, 900 MHz, 1800 MHz, 1900 MHz, 2100 MHz, 2300 MHz, and 2500 MHz. Some devices cover a small wireless communication area; these include mobile phones using Wi-Fi and Bluetooth systems and using frequency bands of 2.4 GHz, 5.2 GHz, and 5.8 GHz.
An antenna is indispensable in a mobile device supporting wireless communication. However, since a mobile device often has limited interior space, there is not sufficient area for accommodating the required antenna element. Accordingly, it becomes a critical challenge for antenna designers to design a novel antenna with a small size and wideband characteristics.